US20110094836A1 - Transmission device - Google Patents
Transmission device Download PDFInfo
- Publication number
- US20110094836A1 US20110094836A1 US12/647,313 US64731309A US2011094836A1 US 20110094836 A1 US20110094836 A1 US 20110094836A1 US 64731309 A US64731309 A US 64731309A US 2011094836 A1 US2011094836 A1 US 2011094836A1
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- US
- United States
- Prior art keywords
- transmission wheel
- driving sleeve
- guiding
- limiting member
- guiding groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D65/00—Parts or details
- F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
- F16D65/16—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake
- F16D65/18—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake adapted for drawing members together, e.g. for disc brakes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2121/00—Type of actuator operation force
- F16D2121/18—Electric or magnetic
- F16D2121/24—Electric or magnetic using motors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2125/00—Components of actuators
- F16D2125/18—Mechanical mechanisms
- F16D2125/20—Mechanical mechanisms converting rotation to linear movement or vice versa
- F16D2125/34—Mechanical mechanisms converting rotation to linear movement or vice versa acting in the direction of the axis of rotation
- F16D2125/36—Helical cams, Ball-rotating ramps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2125/00—Components of actuators
- F16D2125/18—Mechanical mechanisms
- F16D2125/20—Mechanical mechanisms converting rotation to linear movement or vice versa
- F16D2125/34—Mechanical mechanisms converting rotation to linear movement or vice versa acting in the direction of the axis of rotation
- F16D2125/40—Screw-and-nut
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2125/00—Components of actuators
- F16D2125/18—Mechanical mechanisms
- F16D2125/44—Mechanical mechanisms transmitting rotation
- F16D2125/46—Rotating members in mutual engagement
- F16D2125/48—Rotating members in mutual engagement with parallel stationary axes, e.g. spur gears
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2127/00—Auxiliary mechanisms
- F16D2127/06—Locking mechanisms, e.g. acting on actuators, on release mechanisms or on force transmission mechanisms
Definitions
- the invention relates to a transmission device, more particularly to a transmission device capable of preventing reverse transmission.
- FIGS. 1 and 2 illustrate a conventional electric parking brake mechanism 13 disclosed in U.S. Pat. No. 6,938,736.
- the conventional electric parking brake mechanism 13 is characterized by an electric parking brake for pressing a friction member to a braked member via a force transmission converting mechanism 10 for converting a rotational movement of the motor 11 to a linear movement.
- the conventional electric parking brake mechanism 13 includes an input shaft 130 , an output shaft 122 , a non-rotating member 131 , a rotating member 132 , a first cam member 135 , two second cam members 134 , a spring 137 and two balls 136 .
- the first and second cam members 135 , 134 are used, thereby resulting in relatively high cost. Furthermore, when the motor 11 is operated in high-speed rotation, friction between the balls 136 and the non-rotating member 131 occurs due to a centrifugal force acted on each ball 136 , thereby reducing efficiency. Moreover, due to friction between the balls 136 and the non-rotating member 131 , wear of the balls 136 and the non-rotating member 131 occurs, thereby increasing a clearance between each ball 136 and the non-rotating member 131 . Therefore, accurate operation cannot be ensured after a long period of use.
- an object of the present invention is to provide a transmission device that can overcome the aforesaid drawbacks of the prior art.
- a transmission device adapted to be coupled to a drive shaft that is pivotable about a pivot axis.
- the transmission device comprises:
- a mounting frame including an abutting member
- a driving sleeve adapted to be sleeved on the drive shaft such that the driving sleeve co-rotates with the drive shaft, the driving sleeve having an annular outer surface formed with at least one spiral first guiding groove that has opposite first and second ends;
- a transmission wheel formed with an axial hole permitting extension of the driving sleeve thereinto such that the transmission wheel is sleeved rotatably on the driving sleeve, and at least one radially extending through hole in spatial communication with the axial hole and corresponding to the first guiding groove in the driving sleeve, the transmission wheel having a side surface formed with a curved second guiding groove that has opposite first and second ends, the second guiding groove having a depth increasing gradually toward the second end thereof;
- a connecting unit including at least one connecting post extending through the through hole in the transmission wheel and into the first guiding groove in the driving sleeve, and movable in the first guiding groove in the driving sleeve such that the transmission wheel is moved toward the abutting member of the mounting frame in a longitudinal direction parallel to the pivot axis by a first distance when the connecting post is guided by said first guiding groove in the driving sleeve to move from the second end of the first guiding groove to the first end of the first guiding groove in response to rotation of the driving sleeve driven by the drive shaft;
- a position-limiting member disposed movably on the side surface of the transmission wheel, formed with at least one ball-receiving hole corresponding to the second guiding groove in the side surface of the transmission wheel, and rotatable relative to the transmission wheel about the pivot axis between a first position, where the ball-receiving hole is disposed adjacent to the second end of the second guiding groove in the side surface of the transmission wheel, and a second position, where the ball-receiving hole is disposed adjacent to the first end of the second guiding groove in the side surface of the transmission wheel;
- At least one ball disposed in the ball-receiving hole in the position-limiting member, and movable in the second guiding groove in the side surface of the transmission wheel such that the ball moves toward the abutting member of the mounting frame in the longitudinal direction by a second distance when the ball moves from the second end of the second guiding groove in the side surface of the transmission wheel to the first end of the second guiding groove in the side surface of the transmission wheel in response to rotation of the position-limiting member relative to the transmission wheel from the first position to the second position.
- FIG. 1 is a partly schematic sectional view of a conventional electric parking brake mechanism
- FIG. 2 is a schematic view illustrating constitution of the conventional electric parking brake mechanism
- FIG. 3 is an exploded perspective view showing the first preferred embodiment of a transmission device according to the present invention.
- FIG. 4 is an assembled schematic sectional view showing the first preferred embodiment when a drive shaft rotates in a counterclockwise direction;
- FIG. 5 is a partly schematic sectional view illustrating a relationship between a connecting post and a driving sleeve of the first preferred embodiment when the drive shaft rotates in the counterclockwise direction;
- FIG. 6 is a schematic top view illustrating a relationship among balls, a transmission wheel and a position-limiting member of the first preferred embodiment when the drive shaft rotates in the counterclockwise direction;
- FIG. 7 is a fragmentary, partly schematic sectional view illustrating a relationship among one ball, an abutting member and a corresponding second guiding groove of the first preferred embodiment when the drive shaft rotates in the counterclockwise direction;
- FIG. 8 is a schematic sectional view showing the first preferred embodiment when the drive shaft rotates in a clockwise direction
- FIG. 9 is a partly schematic sectional view illustrating a relationship between the connecting post and the driving sleeve of the first preferred embodiment when the drive shaft rotates in the clockwise direction;
- FIG. 10 is a schematic top view illustrating a relationship among the balls, the transmission wheel and the position-limiting member of the first preferred embodiment when the drive shaft rotates in the clockwise direction;
- FIG. 11 is a fragmentary, partly schematic sectional view illustrating a relationship among one ball, the abutting member and a corresponding second guiding groove of the first preferred embodiment when the drive shaft rotates in the clockwise direction;
- FIG. 12 is a schematic sectional view showing the first preferred embodiment when operated in a locking state
- FIG. 13 is a schematic top view illustrating another embodiment of the biasing member.
- FIG. 14 is a schematic sectional view showing the second preferred embodiment of a transmission device according to the present invention when operated in a locking state.
- the first preferred embodiment of a transmission device is shown to include a mounting frame 30 , a driving sleeve 40 , a transmission wheel 50 , a connecting unit 60 , a position-limiting member 90 , three balls 80 , and a biasing member.
- the drive shaft 21 is an output shaft of a motor 20 that is operable to output rotation power for driving a brake mechanism (not shown) via the transmission device and a gear system (not shown), and is pivotable about a pivot axis (I).
- the mounting frame 30 includes a base plate 31 formed with a through hole 311 adapted to permit extension of the drive shaft 21 therethrough, and an abutting member 32 opposite to the base plate 31 in a longitudinal direction (A) parallel to the pivot axis (I).
- the abutting member 32 is a plate body parallel to the base plate 31 .
- the driving sleeve 40 is adapted to be sleeved on the drive shaft 21 such that the driving sleeve 40 co-rotates with the drive shaft 21 .
- the driving sleeve 90 includes a first segment 41 disposed adjacent to the base plate 31 of the mounting frame 30 , a second segment 42 connected to the first segment 41 and having an outer diameter less than that of the first segment 41 , and a third segment 43 opposite to the first segment 41 , connected to the second segment 42 and having an outer diameter less than that of the second segment 42 .
- the second segment 42 of the driving sleeve 40 is formed with two spiral first guiding grooves 44 opposite to each other. Each first guiding groove 44 has a first end 491 , and a second end 442 opposite to the first end 441 and disposed adjacent to the base plate 31 of the mounting frame 30 .
- the transmission wheel 50 is formed with an axial hole 53 permitting extension of the driving sleeve 40 thereinto such that the transmission wheel 50 is sleeved rotatably on the second segment 42 of the driving sleeve 40 .
- the transmission wheel 50 has a connecting end portion 52 , and a transmission end portion 51 opposite to the connecting end portion 52 in the longitudinal direction (A).
- the connecting end portion 52 is formed with two radially extending through holes 54 opposite to each other, in spatial communication with the axial hole 53 and corresponding respectively to the first guiding grooves 49 in the driving sleeve 90 .
- the transmission end portion 51 is in the form of a gear, and has a side surface 512 distal from the base plate 31 of the mounting frame 30 , and formed with three curved second guiding grooves 56 spaced apart from each other, and three mounting holes 550 each disposed between a respective adjacent pair of the second guiding grooves 56 .
- Each second guiding groove 56 has opposite first and second ends 561 , 562 , and has a depth increasing gradually toward the second end 562 , as shown in FIG. 7 .
- the transmission wheel 50 further has three guiding rods 55 mounted respectively in the mounting holes 550 in the side surface 512 and extending outwardly of the side surface 512 in the longitudinal direction (A).
- the side surface 512 of the transmission 50 is further formed with a radially extending first positioning groove 57 in spatial communication with the axial hole 53 .
- the connecting unit 60 includes two connecting posts 61 , and a positioning ring 62 .
- Each connecting post 61 extends through a corresponding through hole 54 in the connecting end portion 52 of the transmission wheel 50 and into a corresponding first guiding groove 44 in the driving sleeve 40 .
- the positioning ring 62 is sleeved on the connecting end portion 52 of the transmission wheel 50 for retaining each connecting post 61 in the corresponding through hole 54 in the connecting end portion 52 of the transmission wheel 50 and the corresponding first guiding groove 44 in the driving sleeve 40 .
- Each connecting post 61 is movable in the corresponding first guiding groove 44 in the driving sleeve 40 (see FIG. 5 ).
- the position-limiting member 90 is in the form of a ring body in this embodiment, and is formed with a center hole 91 having a diameter larger than the outer diameter of the third segment 43 of the driving sleeve 40 .
- the position-limiting member 90 is disposed movably on the side surface 512 of the transmission wheel 50 , and is sleeved spacedly on the third segment 43 of the driving sleeve 40 .
- the position-limiting member 90 is formed with three ball-receiving holes 93 corresponding respectively to the second guiding grooves 56 in the transmission wheel 50 , and three curved rod-guiding holes 92 corresponding respectively to the guiding rods 55 of the transmission wheel 50 .
- Each rod-guiding hole 92 permits extension of a corresponding guiding rod 55 of the transmission wheel 50 therethrough such that each guiding rod 55 of the transmission wheel 50 is movable in the corresponding rod-guiding hole 92 .
- the position-limiting member 90 is rotatable relative to the transmission wheel 50 about the pivot axis (I) between a first position, where each ball-receiving hole 93 is disposed adjacent to the second end 562 of a corresponding second guiding groove 56 in the transmission wheel 50 , as shown in FIGS. 8 and 10 , and a second position, where each ball-receiving hole is disposed adjacent to the first end 561 of a corresponding second guiding groove 56 in the transmission wheel 50 , as shown in FIGS. 4 and 6 .
- each guiding rod 55 of the transmission wheel 50 is in the first end 921 of the corresponding rod-guiding hole 92 , as shown in FIG. 10 .
- each guiding rod 55 of the transmission wheel 50 is in the second end 922 of the corresponding rod-guiding hole 92 , as shown in FIG. 6 .
- the position-limiting member 90 is further formed with a second positioning hole 94 in spatial communication with the center hole 91 (see FIG. 3 ).
- Each ball 80 is disposed in a corresponding ball-receiving hole 93 in the position-limiting member 90 , and is movable in a corresponding second guiding groove 56 in the transmission wheel 50 such that each ball 80 moves toward the abutting member 32 of the mounting frame 30 in the longitudinal direction (A) by a second distance (d 2 ), such as 1.5 mm, when each ball 80 moves from the second end 562 of the corresponding second guiding groove 56 in the transmission wheel 50 to the first end 561 of the corresponding second guiding groove 56 in the transmission wheel 50 in response to rotation of the position-limiting member 90 relative to the transmission wheel 50 from the first position to the second position, as shown in FIG. 11 .
- the ball-receiving holes 93 in the position-limiting member 90 have a diameter greater than that of the balls 80 .
- each connecting post 61 is in the second end 442 of the corresponding first guiding groove 44 in the driving sleeve 40 and when the position-limiting member 90 is at the first position, each ball 80 is spaced apart from the abutting member 32 of the mounting frame 30 , thereby defining a third distance (d 3 ), such as 2 mm, in the longitudinal direction (A) therebetween.
- the third distance (d 3 ) is greater than each of the first and second distances (d 1 , d 2 ) and is less than a sum of the first and second distances (d 1 , d 2 ).
- the biasing member biases the position-limiting member 90 to move relative to the transmission wheel 50 toward the second position.
- the biasing member includes a torsion spring 100 sleeved on the third segment 43 of the driving sleeve 40 , and has opposite first and second end portions 101 , 102 engaging respectively the first positioning groove 57 in the side surface 512 of the transmission wheel 50 and the second positioning groove 94 in the position-limiting member 90 .
- the biasing member includes three compression springs 103 , each of which is received in a corresponding rod-guiding hole 92 in the position-limiting member 90 , and has one end abutting against the guiding rod 55 in the corresponding rod-guiding hole 92 , and the other end disposed in the first end 921 of the corresponding rod-guiding hole 92 .
- each connecting post 61 engages the first end 441 of the corresponding first guiding groove 44 in the driving sleeve 40
- each guiding rod 55 of the transmission wheel engages the first end 921 of the corresponding rod-guiding hole 92 in the position-limiting member 90
- each ball 80 is retained in the second end 562 of the corresponding second guiding groove 56 in the transmission wheel 50 , as shown in FIGS. 8 and 10 .
- each ball 80 is spaced apart from the abutting member 52 by a clearance less than the second distance (d 2 ).
- the drive shaft 21 rotates so as to drive rotation of the assembly of the driving sleeve 40 , the transmission wheel 50 , the position-limiting member 90 and the balls 80 about the pivot axis (I) in a second direction that is reverse to the first direction, such as a counterclockwise direction indicated by an arrow of FIG.
- each connecting post 61 engages the second end 442 of the corresponding first guiding groove 44 in the driving sleeve 40
- each guiding rod 55 of the transmission wheel 50 engages the second end 922 of the corresponding rod-guiding hole 92 in the position-limiting member 90
- each ball 80 is retained in the first end 561 of the corresponding second guiding groove 56 in the transmission wheel 50 , as shown in FIGS. 4 and 6 .
- each ball 80 moves toward the abutting member 32 by the second distance (d 2 )
- each ball 80 is spaced apart from the abutting member 32 by a clearance less than the first distance (d 1 ).
- the brake mechanism can be brought into a brake state via the transmission device and the gear system.
- the brake mechanism can be brought into a releasing-brake state via the transmission device. It is noted that, during the brake state of the brake mechanism, the drive shaft 21 does not rotate once the motor 20 is brought into a stationary state, for example, the motor 20 is shut down. In this case, the driving sleeve 40 is stationary.
- the transmission wheel 50 is driven by a reverse power from the gear system to rotate in the counterclockwise direction.
- each ball 80 moves from the second end 562 of the corresponding second guiding groove 56 in the transmission wheel 50 to the first end 561 of the same, thereby moving toward the abutting member 32 , as shown in FIG. 11 . Since the clearance between each ball 80 and the abutting member 32 is less the second distance (d 2 ), the balls 80 are clamped between the abutting member 32 and the transmission wheel 50 , thereby terminating rotation of the transmission wheel 50 . In this case, the transmission device is brought into a locking state. As such, the brake mechanism can be held in the brake state. Thereafter, when the drive shaft 21 is operable to drive clockwise rotation of the driving sleeve 40 , the balls 80 are released from the abutting member 32 .
- FIG. 15 illustrates the second preferred embodiment of a transmission device according to this invention, which is a modification of the first preferred embodiment.
- the abutting member 32 i.e., the plate body of the mounting frame 30 ′, has a surface 320 facing the position-limiting member 90 and formed with an annular groove 321 that is defined by a concave wall.
- the transmission device further includes a bearing 33 adapted to be sleeved on the drive shaft 21 and disposed between the base plate 31 of the mounting frame 30 and the driving sleeve 40 . It is noted that when the transmission device is in the locking state, the balls 80 are easily clamped due to relatively large frictions between the concave wall of the abutting member 32 ′ and the balls 80 .
- the transmission device of the present invention can be accurately operated without the wear problem encountered in the aforesaid prior art. Furthermore, since expensive cam components in the aforesaid prior art are not required, the transmission device of the present invention can be manufactured at relatively low costs as compared to the aforesaid prior art.
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- Engineering & Computer Science (AREA)
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- Transmission Devices (AREA)
Abstract
Description
- 1. Field of the Invention
- The invention relates to a transmission device, more particularly to a transmission device capable of preventing reverse transmission.
- 2. Description of the Related Art
-
FIGS. 1 and 2 illustrate a conventional electricparking brake mechanism 13 disclosed in U.S. Pat. No. 6,938,736. The conventional electricparking brake mechanism 13 is characterized by an electric parking brake for pressing a friction member to a braked member via a forcetransmission converting mechanism 10 for converting a rotational movement of themotor 11 to a linear movement. The conventional electricparking brake mechanism 13 includes an input shaft 130, anoutput shaft 122, anon-rotating member 131, a rotatingmember 132, afirst cam member 135, twosecond cam members 134, aspring 137 and twoballs 136. - In such a configuration, the first and
second cam members motor 11 is operated in high-speed rotation, friction between theballs 136 and the non-rotatingmember 131 occurs due to a centrifugal force acted on eachball 136, thereby reducing efficiency. Moreover, due to friction between theballs 136 and thenon-rotating member 131, wear of theballs 136 and thenon-rotating member 131 occurs, thereby increasing a clearance between eachball 136 and the non-rotatingmember 131. Therefore, accurate operation cannot be ensured after a long period of use. - Therefore, an object of the present invention is to provide a transmission device that can overcome the aforesaid drawbacks of the prior art.
- According to the present invention, there is provided a transmission device adapted to be coupled to a drive shaft that is pivotable about a pivot axis. The transmission device comprises:
- a mounting frame including an abutting member;
- a driving sleeve adapted to be sleeved on the drive shaft such that the driving sleeve co-rotates with the drive shaft, the driving sleeve having an annular outer surface formed with at least one spiral first guiding groove that has opposite first and second ends;
- a transmission wheel formed with an axial hole permitting extension of the driving sleeve thereinto such that the transmission wheel is sleeved rotatably on the driving sleeve, and at least one radially extending through hole in spatial communication with the axial hole and corresponding to the first guiding groove in the driving sleeve, the transmission wheel having a side surface formed with a curved second guiding groove that has opposite first and second ends, the second guiding groove having a depth increasing gradually toward the second end thereof;
- a connecting unit including at least one connecting post extending through the through hole in the transmission wheel and into the first guiding groove in the driving sleeve, and movable in the first guiding groove in the driving sleeve such that the transmission wheel is moved toward the abutting member of the mounting frame in a longitudinal direction parallel to the pivot axis by a first distance when the connecting post is guided by said first guiding groove in the driving sleeve to move from the second end of the first guiding groove to the first end of the first guiding groove in response to rotation of the driving sleeve driven by the drive shaft;
- a position-limiting member disposed movably on the side surface of the transmission wheel, formed with at least one ball-receiving hole corresponding to the second guiding groove in the side surface of the transmission wheel, and rotatable relative to the transmission wheel about the pivot axis between a first position, where the ball-receiving hole is disposed adjacent to the second end of the second guiding groove in the side surface of the transmission wheel, and a second position, where the ball-receiving hole is disposed adjacent to the first end of the second guiding groove in the side surface of the transmission wheel; and
- at least one ball disposed in the ball-receiving hole in the position-limiting member, and movable in the second guiding groove in the side surface of the transmission wheel such that the ball moves toward the abutting member of the mounting frame in the longitudinal direction by a second distance when the ball moves from the second end of the second guiding groove in the side surface of the transmission wheel to the first end of the second guiding groove in the side surface of the transmission wheel in response to rotation of the position-limiting member relative to the transmission wheel from the first position to the second position.
- Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
-
FIG. 1 is a partly schematic sectional view of a conventional electric parking brake mechanism; -
FIG. 2 is a schematic view illustrating constitution of the conventional electric parking brake mechanism; -
FIG. 3 is an exploded perspective view showing the first preferred embodiment of a transmission device according to the present invention; -
FIG. 4 is an assembled schematic sectional view showing the first preferred embodiment when a drive shaft rotates in a counterclockwise direction; -
FIG. 5 is a partly schematic sectional view illustrating a relationship between a connecting post and a driving sleeve of the first preferred embodiment when the drive shaft rotates in the counterclockwise direction; -
FIG. 6 is a schematic top view illustrating a relationship among balls, a transmission wheel and a position-limiting member of the first preferred embodiment when the drive shaft rotates in the counterclockwise direction; -
FIG. 7 is a fragmentary, partly schematic sectional view illustrating a relationship among one ball, an abutting member and a corresponding second guiding groove of the first preferred embodiment when the drive shaft rotates in the counterclockwise direction; -
FIG. 8 is a schematic sectional view showing the first preferred embodiment when the drive shaft rotates in a clockwise direction; -
FIG. 9 is a partly schematic sectional view illustrating a relationship between the connecting post and the driving sleeve of the first preferred embodiment when the drive shaft rotates in the clockwise direction; -
FIG. 10 is a schematic top view illustrating a relationship among the balls, the transmission wheel and the position-limiting member of the first preferred embodiment when the drive shaft rotates in the clockwise direction; -
FIG. 11 is a fragmentary, partly schematic sectional view illustrating a relationship among one ball, the abutting member and a corresponding second guiding groove of the first preferred embodiment when the drive shaft rotates in the clockwise direction; -
FIG. 12 is a schematic sectional view showing the first preferred embodiment when operated in a locking state; -
FIG. 13 is a schematic top view illustrating another embodiment of the biasing member; and -
FIG. 14 is a schematic sectional view showing the second preferred embodiment of a transmission device according to the present invention when operated in a locking state. - Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
- Referring to
FIGS. 3 and 4 , the first preferred embodiment of a transmission device according to the present invention is shown to include amounting frame 30, adriving sleeve 40, atransmission wheel 50, a connectingunit 60, a position-limitingmember 90, threeballs 80, and a biasing member. In this embodiment, thedrive shaft 21 is an output shaft of amotor 20 that is operable to output rotation power for driving a brake mechanism (not shown) via the transmission device and a gear system (not shown), and is pivotable about a pivot axis (I). - The
mounting frame 30 includes abase plate 31 formed with athrough hole 311 adapted to permit extension of thedrive shaft 21 therethrough, and anabutting member 32 opposite to thebase plate 31 in a longitudinal direction (A) parallel to the pivot axis (I). In this embodiment, theabutting member 32 is a plate body parallel to thebase plate 31. - The
driving sleeve 40 is adapted to be sleeved on thedrive shaft 21 such that the driving sleeve 40 co-rotates with thedrive shaft 21. In this embodiment, thedriving sleeve 90 includes afirst segment 41 disposed adjacent to thebase plate 31 of themounting frame 30, asecond segment 42 connected to thefirst segment 41 and having an outer diameter less than that of thefirst segment 41, and athird segment 43 opposite to thefirst segment 41, connected to thesecond segment 42 and having an outer diameter less than that of thesecond segment 42. Thesecond segment 42 of thedriving sleeve 40 is formed with two spiral first guidinggrooves 44 opposite to each other. Each first guidinggroove 44 has a first end 491, and asecond end 442 opposite to thefirst end 441 and disposed adjacent to thebase plate 31 of themounting frame 30. - The
transmission wheel 50 is formed with anaxial hole 53 permitting extension of thedriving sleeve 40 thereinto such that thetransmission wheel 50 is sleeved rotatably on thesecond segment 42 of thedriving sleeve 40. In this embodiment, thetransmission wheel 50 has a connectingend portion 52, and atransmission end portion 51 opposite to the connectingend portion 52 in the longitudinal direction (A). The connectingend portion 52 is formed with two radially extending throughholes 54 opposite to each other, in spatial communication with theaxial hole 53 and corresponding respectively to the first guiding grooves 49 in thedriving sleeve 90. Thetransmission end portion 51 is in the form of a gear, and has aside surface 512 distal from thebase plate 31 of themounting frame 30, and formed with three curved second guidinggrooves 56 spaced apart from each other, and threemounting holes 550 each disposed between a respective adjacent pair of the second guidinggrooves 56. Eachsecond guiding groove 56 has opposite first andsecond ends second end 562, as shown inFIG. 7 . Thetransmission wheel 50 further has three guidingrods 55 mounted respectively in themounting holes 550 in theside surface 512 and extending outwardly of theside surface 512 in the longitudinal direction (A). In this embodiment, theside surface 512 of thetransmission 50 is further formed with a radially extendingfirst positioning groove 57 in spatial communication with theaxial hole 53. - In this embodiment, the connecting
unit 60 includes two connectingposts 61, and apositioning ring 62. Each connectingpost 61 extends through a corresponding throughhole 54 in the connectingend portion 52 of thetransmission wheel 50 and into a corresponding first guidinggroove 44 in thedriving sleeve 40. Thepositioning ring 62 is sleeved on the connectingend portion 52 of thetransmission wheel 50 for retaining each connectingpost 61 in the corresponding throughhole 54 in the connectingend portion 52 of thetransmission wheel 50 and the corresponding first guidinggroove 44 in thedriving sleeve 40. Each connectingpost 61 is movable in the corresponding first guidinggroove 44 in the driving sleeve 40 (seeFIG. 5 ). Therefore, when each connectingpost 61 is guided by the corresponding first guidinggroove 44 in thedriving sleeve 40 from thesecond end 442 thereof to thefirst end 441 thereof in response to rotation of thedriving sleeve 40 driven by thedrive shaft 21, thetransmission wheel 50 is moved toward theabutting member 32 of themounting frame 30 in the longitudinal direction (A) by a first distance (d1), such as 1.5 mm, as shown inFIG. 9 . - The position-limiting
member 90 is in the form of a ring body in this embodiment, and is formed with acenter hole 91 having a diameter larger than the outer diameter of thethird segment 43 of thedriving sleeve 40. The position-limitingmember 90 is disposed movably on theside surface 512 of thetransmission wheel 50, and is sleeved spacedly on thethird segment 43 of thedriving sleeve 40. The position-limitingmember 90 is formed with three ball-receivingholes 93 corresponding respectively to thesecond guiding grooves 56 in thetransmission wheel 50, and three curved rod-guidingholes 92 corresponding respectively to the guidingrods 55 of thetransmission wheel 50. Each rod-guidinghole 92 permits extension of a corresponding guidingrod 55 of thetransmission wheel 50 therethrough such that each guidingrod 55 of thetransmission wheel 50 is movable in the corresponding rod-guidinghole 92. As a result, the position-limitingmember 90 is rotatable relative to thetransmission wheel 50 about the pivot axis (I) between a first position, where each ball-receivinghole 93 is disposed adjacent to thesecond end 562 of a corresponding second guidinggroove 56 in thetransmission wheel 50, as shown inFIGS. 8 and 10 , and a second position, where each ball-receiving hole is disposed adjacent to thefirst end 561 of a corresponding second guidinggroove 56 in thetransmission wheel 50, as shown inFIGS. 4 and 6 . When the position-limitingmember 90 is at the first position, each guidingrod 55 of thetransmission wheel 50 is in thefirst end 921 of the corresponding rod-guidinghole 92, as shown inFIG. 10 . When the position-limitingmember 90 is at the second position, each guidingrod 55 of thetransmission wheel 50 is in thesecond end 922 of the corresponding rod-guidinghole 92, as shown inFIG. 6 . In this embodiment, the position-limitingmember 90 is further formed with asecond positioning hole 94 in spatial communication with the center hole 91 (seeFIG. 3 ). - Each
ball 80 is disposed in a corresponding ball-receivinghole 93 in the position-limitingmember 90, and is movable in a corresponding second guidinggroove 56 in thetransmission wheel 50 such that eachball 80 moves toward the abuttingmember 32 of the mountingframe 30 in the longitudinal direction (A) by a second distance (d2), such as 1.5 mm, when eachball 80 moves from thesecond end 562 of the corresponding second guidinggroove 56 in thetransmission wheel 50 to thefirst end 561 of the corresponding second guidinggroove 56 in thetransmission wheel 50 in response to rotation of the position-limitingmember 90 relative to thetransmission wheel 50 from the first position to the second position, as shown inFIG. 11 . In this embodiment, the ball-receivingholes 93 in the position-limitingmember 90 have a diameter greater than that of theballs 80. - It is noted that, each connecting
post 61 is in thesecond end 442 of the corresponding first guidinggroove 44 in the drivingsleeve 40 and when the position-limitingmember 90 is at the first position, eachball 80 is spaced apart from the abuttingmember 32 of the mountingframe 30, thereby defining a third distance (d3), such as 2 mm, in the longitudinal direction (A) therebetween. The third distance (d3) is greater than each of the first and second distances (d1, d2) and is less than a sum of the first and second distances (d1, d2). - The biasing member biases the position-limiting
member 90 to move relative to thetransmission wheel 50 toward the second position. In this embodiment, the biasing member includes atorsion spring 100 sleeved on thethird segment 43 of the drivingsleeve 40, and has opposite first andsecond end portions first positioning groove 57 in theside surface 512 of thetransmission wheel 50 and thesecond positioning groove 94 in the position-limitingmember 90.FIG. 14 illustrates another embodiment of the biasing member, wherein the biasing member includes threecompression springs 103, each of which is received in a corresponding rod-guidinghole 92 in the position-limitingmember 90, and has one end abutting against the guidingrod 55 in the corresponding rod-guidinghole 92, and the other end disposed in thefirst end 921 of the corresponding rod-guidinghole 92. - In actual operation, when the
drive shaft 21 rotates so as to drive rotation of an assembly of the drivingsleeve 40, thetransmission wheel 50, the position-limitingmember 90 and theballs 80 about the pivot axis (I) in a first direction, such as a clockwise direction indicated by an arrow ofFIG. 10 , each connectingpost 61 engages thefirst end 441 of the corresponding first guidinggroove 44 in the drivingsleeve 40, each guidingrod 55 of the transmission wheel engages thefirst end 921 of the corresponding rod-guidinghole 92 in the position-limitingmember 90, and eachball 80 is retained in thesecond end 562 of the corresponding second guidinggroove 56 in thetransmission wheel 50, as shown inFIGS. 8 and 10 . In this case, though thetransmission wheel 50 is moved relative to the drivingsleeve 40 toward the abuttingmember 32 by the first distance (d1), eachball 80 is spaced apart from the abuttingmember 52 by a clearance less than the second distance (d2). On the other hand, when thedrive shaft 21 rotates so as to drive rotation of the assembly of the drivingsleeve 40, thetransmission wheel 50, the position-limitingmember 90 and theballs 80 about the pivot axis (I) in a second direction that is reverse to the first direction, such as a counterclockwise direction indicated by an arrow ofFIG. 6 , each connectingpost 61 engages thesecond end 442 of the corresponding first guidinggroove 44 in the drivingsleeve 40, each guidingrod 55 of thetransmission wheel 50 engages thesecond end 922 of the corresponding rod-guidinghole 92 in the position-limitingmember 90, and eachball 80 is retained in thefirst end 561 of the corresponding second guidinggroove 56 in thetransmission wheel 50, as shown inFIGS. 4 and 6 . In this case, though eachball 80 moves toward the abuttingmember 32 by the second distance (d2), eachball 80 is spaced apart from the abuttingmember 32 by a clearance less than the first distance (d1). - In use, when the
drive shaft 21 rotates in the clockwise direction, the brake mechanism can be brought into a brake state via the transmission device and the gear system. When thedrive shaft 21 rotates in the counterclockwise direction, the brake mechanism can be brought into a releasing-brake state via the transmission device. It is noted that, during the brake state of the brake mechanism, thedrive shaft 21 does not rotate once themotor 20 is brought into a stationary state, for example, themotor 20 is shut down. In this case, the drivingsleeve 40 is stationary. At the same time, thetransmission wheel 50 is driven by a reverse power from the gear system to rotate in the counterclockwise direction. As a result, eachball 80 moves from thesecond end 562 of the corresponding second guidinggroove 56 in thetransmission wheel 50 to thefirst end 561 of the same, thereby moving toward the abuttingmember 32, as shown inFIG. 11 . Since the clearance between eachball 80 and the abuttingmember 32 is less the second distance (d2), theballs 80 are clamped between the abuttingmember 32 and thetransmission wheel 50, thereby terminating rotation of thetransmission wheel 50. In this case, the transmission device is brought into a locking state. As such, the brake mechanism can be held in the brake state. Thereafter, when thedrive shaft 21 is operable to drive clockwise rotation of the drivingsleeve 40, theballs 80 are released from the abuttingmember 32. -
FIG. 15 illustrates the second preferred embodiment of a transmission device according to this invention, which is a modification of the first preferred embodiment. In this embodiment, the abuttingmember 32, i.e., the plate body of the mountingframe 30′, has asurface 320 facing the position-limitingmember 90 and formed with anannular groove 321 that is defined by a concave wall. Furthermore, the transmission device further includes abearing 33 adapted to be sleeved on thedrive shaft 21 and disposed between thebase plate 31 of the mountingframe 30 and the drivingsleeve 40. It is noted that when the transmission device is in the locking state, theballs 80 are easily clamped due to relatively large frictions between the concave wall of the abuttingmember 32′ and theballs 80. - In sum, due to the presence of the first guiding
grooves 44, thesecond guiding grooves 56 and the position-limitingmember 90, the transmission device of the present invention can be accurately operated without the wear problem encountered in the aforesaid prior art. Furthermore, since expensive cam components in the aforesaid prior art are not required, the transmission device of the present invention can be manufactured at relatively low costs as compared to the aforesaid prior art. - While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
Claims (12)
Applications Claiming Priority (2)
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TW098135780A TW201115046A (en) | 2009-10-22 | 2009-10-22 | Transmission device capable of preventing reverse rotation |
TW098135780 | 2009-10-22 |
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US20110094836A1 true US20110094836A1 (en) | 2011-04-28 |
US8839935B2 US8839935B2 (en) | 2014-09-23 |
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US12/647,313 Active 2033-06-27 US8839935B2 (en) | 2009-10-22 | 2009-12-24 | Transmission device |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150362031A1 (en) * | 2014-06-17 | 2015-12-17 | Mando Corporation | Electric disk brake |
JP2022167897A (en) * | 2021-07-20 | 2022-11-04 | ファーウェイ デジタル パワー テクノロジーズ カンパニー リミテッド | Parking mechanism, emb system, and vehicle |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI680241B (en) * | 2018-03-26 | 2019-12-21 | 黃奕誠 | Improved mechanical disc brake structure |
CN108999894B (en) * | 2018-08-08 | 2021-03-02 | 王晓东 | Mechanical bidirectional automatic clutch meeting low rotating speed |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6938736B2 (en) * | 2002-11-26 | 2005-09-06 | Akebono Brake Industry Co., Ltd. | Electric parking brake mechanism |
-
2009
- 2009-10-22 TW TW098135780A patent/TW201115046A/en unknown
- 2009-12-24 US US12/647,313 patent/US8839935B2/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6938736B2 (en) * | 2002-11-26 | 2005-09-06 | Akebono Brake Industry Co., Ltd. | Electric parking brake mechanism |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150362031A1 (en) * | 2014-06-17 | 2015-12-17 | Mando Corporation | Electric disk brake |
US9441691B2 (en) * | 2014-06-17 | 2016-09-13 | Mando Corporation | Electric disk brake |
DE102015007495B4 (en) | 2014-06-17 | 2021-07-29 | Mando Corporation | Electric disc brake |
JP2022167897A (en) * | 2021-07-20 | 2022-11-04 | ファーウェイ デジタル パワー テクノロジーズ カンパニー リミテッド | Parking mechanism, emb system, and vehicle |
EP4122786A1 (en) * | 2021-07-20 | 2023-01-25 | Huawei Digital Power Technologies Co., Ltd. | Parking mechanism, electronic mechanical brake system, and vehicle |
JP7371176B2 (en) | 2021-07-20 | 2023-10-30 | ファーウェイ デジタル パワー テクノロジーズ カンパニー リミテッド | Parking mechanisms, EMB systems, and vehicles |
Also Published As
Publication number | Publication date |
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US8839935B2 (en) | 2014-09-23 |
TW201115046A (en) | 2011-05-01 |
TWI372827B (en) | 2012-09-21 |
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